MEAT IS PROHIBITED.
FISH IS PERMITTED.
Our custom is to abstain from meat and wine during the nine days. It is not our place to rationalize "well this burger is low-quality and this sushi is high-quality ..." before you know it, people would rationalize away the entire custom. Ramban observes that the Torah prohibits exchanging a holy cow for a different ...

I was taught as a child to wear several sets of clothing one after another for a short period of time in the days prior to 1 Av, and I've encountered others who follow the same advice, though the time varies (half-hour, 1 hour, 2 hours).
As I grew older and became responsible for my own time and personal hygiene, I began running into a problem of not having ...

The Rama rules in OC 558 that the prohibitions on wine and meat remain in force for only the night of 11 Av. The Mishna Berura (sk 4) notes that this is meant to be specific, and the other prohibitions do not apply immediately following the fast.

Rabbi B'tzal'el Stern (B'tzel Hachochma volume 4 number 100) was asked whether a minor's siyum exempts an adult from taanis b'choros.
He cites the Rambam (Hilchos Korban Pesach 5:7) as saying that someone who became an adult between Pesach and Pesach sheni need not offer the korban pesach sheni. The explanation of this Rambam is that, because the Torah says ...

Seth, all of the detailed laws regarding when you don't have to worry about listening to music and when you do are really just applications of a single broader law: When Av comes around, we restrict our joy. Actions that are done for joy are improper. If they are done for other reasons, thats OK.
For example, building for joy is prohibited. So I can't ...

The Chazon Ish (quoted in Imrei Yosher, pg. 4) says that those who say Havdalah every week over wine or grape juice should do the same during the Nine Days as well.
In some places it is customary for a minor, if one is present, to drink the wine. The minor who serves the purpose should be a boy beyond the age of chinuch but who is not yet old enough to ...

R. Moshe Feinstein zt"l says (Igros Moshe, vol. 5 (Orach Chaim part 3), no. 80) that one may buy them even during the Nine Days, "because it is solely for the purpose of a mitzvah." (By contrast, he says that one should not buy a new tallis during this time, because it is a garment and is subject to the same laws.)

The Aruch HaShulchan in OH 551:25 writes, after quoting the Ramo in the question:
ומובן ממילא דבעיר גדולה שיש בה תמיד כמה חולאים וכמה יולדות, והרבה חלושי הבריאות – לא שייך להצניע הסכין
"And it is understood automatically that in a big city where there always many sick people and many women who have given birth and many weak people -- it is not relevant to ...

Today's HalachaText said that clothing should be worn for at least 30 minutes. I asked them for a source and they said this number came from Rav Elyashiv Ztl.
שוב מצאתי I was looking for something else in Rabbi Simcha Bunim Cohen's Laws of the Three Weeks, and found that he quotes Rav YS Elyashiv there as saying a half an hour (page 85); in a footnote he ...

You do have a good argument, since the reasoning for starting the restrictions from Rosh Chodesh is the ominous month of Av, which has no standing without the sanctification of the Sanhedrin, which was done in the day.
However, in these matters everything is according to the custom. The Magen Avraham (O.C. 551:26) indicates that it starts at night. ...

According to R' Moshe Soloveichik, during the 9 days the level of mourning is as during the Shloshim mourning period.
In the time of the Shulchan Aruch part of the mourning process during the Shloshim was not to bathe. As such, The Shulchan Aruch (Orach Chaim 551:16) records a custom practiced by Ashkenazim of not bathing or showering during the Nine Days.
...

It's certainly worse than giving it to a gentile laundry to do which is forbidden by the Rema in 551:3. Although the MB there (sk 34) saying it's because of minhag is going on the MA who extends the halacha to one whose intention is for the launderer to clean it after Tisha B'Av, the mashmaos is going on both (it's the same action/issur).

The Shulchan Aruch (551:4) rules regarding both the case of Tisha b'Av on Saturday and Tisha b'Av on Sunday that there is no mourning period and some say (Yesh Omrim) that there is mourning the entire preceding week. Generally when the Shulchan Aruch quotes two opinions and only the latter is prefaced by 'some say', the halacha follows the former opinion ...

Sefer HaToda'ah, authored by R' Eliyahu Ki Tov says in (part 2, page 374):
‫וכבר נתפשט המגהג שלא לאכול אפילו תבשיל שנתבשל‬
‫בו בשר. אבל מותר לאכול תבשיל שיתבשל בקדרה של בשר.‬‏
The custom to not eat even a cooked item that has been cooked with meat has already become popular. But it is permissible to eat a cooked item that was cooked in a meat ...

The Rama writes meat and wine by a seudas mitzvah davka and the food can only be eaten in the room of the siyum(Mishna Brurah 551:75).It seems that meat and wine are the only exception and it only applies during the seudah,not the rest of the day.
It should be noted that planning a siyum to davka come out during the nine days is not so pashut,even though ...

These questions are dealt with here:
The Shulchan Aruch (OC 551:9) writes that one mustn’t eat meat or drink wine during the nine days. The Rema (OC 551:10) adds that if one has a seudas mitzva during this time then one may partake of wine and meat as such celebrations are incomplete without them. This includes Shabbos meals, a bris seuda, a pidyon ...

The source for those who begin one verse earlier is the Eishel Abraham of Butatach (Siman 138) who explains that this is because the custom is to chant the verse "Eicha Esa Levadi" in the same tune as Megillas Eicha and it is therefore considered a "tochecha" (reproach) and we do not begin an Aliyah negatively. See also the Likutey Maharich (3:52:1) who ...

The Shaarei Teshuva (OC 556) quotes those who require the ill person to recite Havadala "right away after Shabbat", though as Rav Ovadia Yosef (Yechavveh Daat 3:40) explains while citing many sources, this means as soon as they need to eat NOT right away on Saturday night if they can last until later in the day. This is indeed how Rav Yosef rules.

The book שערי נחמה (page נ"ה section ט) says the following verses are the ones which are read in regular (non-sad) trop, according to the custom of the yeshivot (the ashkenazi ones, I assume) in Eretz Yisrael:
verse 1
verses 16 to 19
verses 24 to 27
All other verses are read in sad trop.

R'SimchasTorah's answer seems to cover many bases, but since the question seems to be asking specifically for as many people's respective customs as possible, I'll add my family's: we use chamar m'dina.

Supplementing, not supplanting, SethJ's good answer, I've known people to put their clothes on the floor and tread on them. Note, however, that I do not know about the halachic status of this action (whether it suffices for these purposes).

By asking about Shavu'a sheChal Bo, I assume you are looking for a Sephardi perspective. Maran writes (Shulchan Aruch OC 551:10):
ומותר לשתות יין הבדלה וברכת המזון.‏
It is permitted to drink the wine of Havdalah and Birkat haMazon.
The Rama there notes the Ashkenazi practice of refraining from drinking both of those and instead letting a child ...

It seems you are asking if "freshly laundered" means not worn since the last time they were laundered or if it means that they just came out of the laundry recently (time-wise). Obviously, the phrase "freshly laundered" doesn't show up in the Shulchan Aruch, but looking at what he does say (OC 551:3):
וכן המכובסים מקודם, בין ללבוש בין להציע בהם המטה‏
...

It seems that both reasons are applicable.
See Rama in Shulchan Aruch 551:16 which says that bathing for pleasure is prohibited.
See Shulchan Aruch 551:1 and 551:18 which says that when the month of av comes in the more one should be careful and then says later on that certain parts of the day are more dangerous(see Mishna Brurah on 551:18).
The Medrash ...